1. Field of the Invention
The present invention relates to a method of manufacturing a surface-emitting backlight and a surface-emitting backlight manufactured by the method.
2. Description of Related Art
Conventional surface-emitting backlights used for liquid crystal displays, etc. is comprised of a light source, a transparent resin plate (light guide plate) for guiding light from the light source, a lower plate, a diffuser sheet or lens sheet, and an upper case. As the light source, an LED unit in which chip LEDs are attached to a board is used.
According to a conventional manufacturing method, the light guide plate, case, light source, and board of the light source are prepared as independent parts, and are assembled manually into the finished product.
However, according to this conventional method, in the case of a side-edge-type backlight that causes the light source to emit light horizontally with respect to its emissive surface, the upper case must have a certain thickness to allow the light source board to be attached to its side wall, and from this arises a problem that there is a limit to realizing smaller and thinner backlight.
Further, the chip LED has a narrow angle of radiation of light. Thus, in the case of an underneath-type-backlight that causes the light source to emit light vertically with respect to their emissive surface, a large area must be secured in their emissive surface for radiation of light. This requires the underneath-type-backlight to give a certain length to the optical path between the lower surface of the case to the emissive surface, hence making it difficult to implement smaller and thinner backlight.
Still further, the components of these backlights, which are manufactured and conveyed as independent parts, are susceptible to mechanical damage during conveyance and contamination with dust during assembly.
Even further, small liquid crystal displays use small backlights. Thus, manual assembly of the parts of such small backlights is extremely difficult to perform, hence imposing a problem that operating efficiency is impaired.
Especially, the conventional technique of attaching the light source board to the upper case requires that signal lines for supplying power to the light source be soldered to the board, and this operation is extremely cumbersome.